To assess the correlation between the status of the inner segment/outer segment junction (IS/OS) and visual acuity in retinitis pigmentosa.Methods
One hundred and ninety-six eyes of 100 patients with RP were examined with the spectral optical coherence tomography (3D-OCT-2000). The status of the inner segment/outer segment junction (IS/OS) (Grade 1: absent, Grade 2: blurred discontinuous, or Grade 3: distinct) was evaluated. Correlation between visual acuity and each of the measurements were examined.Results
Of the 196 eyes, IS/OS was absent in 61 eyes (30.9%), blurred in 71 eyes (36.36%) and distinct in 64 eyes (32.74%).Total retinal thickness was not correlated with visual acuity. The mean logMAR visual acuity (VA) in the IS/OS absent group (0.65±0.12) was worse than the one seen in the IS/OS blurred (0.23±0.41) or IS/OS distinct groups (0.08±0.44) (P<0.001). But eighteen per cent of the eyes with a normal foveal IS/OS line, normal COST line and normal perifoveal layers have a bad visual acuity. While seven per cent of eyes with absent foveal IS/OS line have surprisingly a good visual acuity.Conclusion
The status of photoreceptor IS/OS line is an important parameter that needs to be examined in RP patients, while perifoveal retinal layers need not be examined. The presence of the foveal photoreceptor IS/OS line is associated with better visual acuity and thicker fovea in RP patients. But, in a few cases, the foveal photoreceptor IS/OS line can be absent with a good visual acuity.